New Species of the Mud Crab Eurypanopeus depressus (Smith, 1869) (Brachyura: Xanthoidea: Panopeidae) in the Sea of Azov

The presence of Eurypanopeus depressus (Smith, 1869) was recorded for the first time in the Sea of Azov during a taxonomic revision of mud crab specimens (fam. Panopeidae) collected between 2022 and 2024. Previously, this species was known only from the Atlantic coasts of America and the western Black Sea. DNA sequences of two nuclear (18S, H3) and two mitochondrial (COI, 16S) gene regions were obtained from the collected individuals, enabling the assessment of genetic diversity and the calculation of genetic distances. The study presents data on the distribution and morphological variability of specimens from the Sea of Azov, along with a detailed description of their preferred habitats. Diagnostic morphological characteristics are provided to facilitate identification of all nonnative mud crab species in the Azov-Black Sea region. The presumed pathways of introduction and subsequent dispersal of the species are discussed, as well as its potential ecological role and significance in the Sea of Azov.